Various types of flat cable are known for use in electrical circuits. Flat cable such as ribbon cable has a plurality of conductors disposed in side-by-side spaced relationship and enclosed in an insulative sheath. Another type of flat cable known as flat power cable is entering commercial use for transmitting electrical power of, for example, 75 amperes nominal. Such flat power cable is about one inch wide and may comprise a single flat conductor such as 0.020 inch thick copper or aluminum with an insulative coating of between 0.004 and 0.008 inch thickness extruded therearound. Also entering commercial acceptance is a dual conductor flat power cable, wherein a pair of co-planar flat conductor strips having insulation extruded therearound define power and return paths for electrical power transmission. The dual conductor strips are spaced approximately 0.100 inch apart, and the insulation which surrounds the strips also fills the gap therebetween.
Electrical connectors are known for terminating dual conductor flat power cable. U.S. Pat. No. 4,915,650 discloses an electrical connector for terminating an end of a dual conductor flat power cable, the terminated end being matable with a corresponding terminated end of another cable, or with a bus bar or power supply, for example. U.S. Pat. No. 5,219,303 discloses a connector for interconnecting a pair of dual flat power cables at a location along a continuous length of at least one of the cables.
The connectors disclosed in the above-referenced patents include terminal assemblies having upper and lower plate sections defining opposed cooperative arrays of conductor engaging members which receive the dual conductor flat power cable therebetween. Prior to terminating a cable, a slot is punched in the cable along its median, thereby removing a short length of the insulative coating between the conductor strips. The terminal assembly is applied to the cable by pressing together the upper and lower plate sections, whereby the conductor engaging members pierce the dual conductor strips of the cable and become interengaged. In a simultaneous operation, central ligatures of the upper and lower plate sections are severed, thereby providing discrete terminals corresponding to the two conductors of the dual power cable so as to enable separate connections to discrete circuits. A dielectric housing is ultimately applied to the terminals to seal out dirt and enable connection to mating terminated cable.
The above-described operation of punching a slot in the cable requires a close tolerance on the position of the slot, for example, the center of the slot to be within 0.010 inch of true position of the center of the cable. If the slot is not positioned within tolerance, the slot will extend unacceptably into one of the dual conductor strips, thereby reducing a width of the strip and preventing secure engagement of the strip by the conductor engaging members of the terminal assembly to be applied.
A machine for punching the slot typically includes a track in which the cable is inserted to position the cable with respect to a punch press. In prior art machines, the track comprises a pair of fixed guides having opposed cable guide surfaces which are spaced apart by a width of the cable so that the cable can be received therebetween. When the cable is centered between the guide surfaces, the median of the cable is aligned with the punching die so that a slot can be punched centrally through the cable. However, there is a manufacturing tolerance on the cable width and, in order for the track to accommodate all cable widths, the guide surfaces are spaced apart by a fixed distance equal to a cable width at the high end of its tolerance range. For example, a typical cable having a width of 1.012 plus or minus 0.013 inch requires the track to have guide surfaces spaced 1.025 inch apart. This results in a problem in that when a cable having a width at the low end of its tolerance range is inserted into the track, the cable has a substantial clearance between the guide surfaces and can not be accurately centered in the track, thereby preventing accurate punching of the slot in the cable. The present invention overcomes this problem by providing a lateral positioning apparatus having an adjustable track width so that cables having different widths may be accurately positioned laterally in a machine for punching a slot in the cable or for performing some other operation on the cable.